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<span id="OpenACC"></span><div class="header">
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<span id="OpenACC-1"></span><h4 class="subsection">5.1.19 OpenACC</h4>
<span id="index-OpenACC-1"></span>

<p>OpenACC is an application programming interface (API) that supports
offloading of code to accelerator devices.  It consists of a set of
compiler directives, library routines, and environment variables that
influence run-time behavior.
</p>
<p>GNU Fortran strives to be compatible to the
<a href="https://www.openacc.org/">OpenACC Application Programming
Interface v2.6</a>.
</p>
<p>To enable the processing of the OpenACC directive <code>!$acc</code> in
free-form source code; the <code>c$acc</code>, <code>*$acc</code> and <code>!$acc</code>
directives in fixed form; the <code>!$</code> conditional compilation
sentinels in free form; and the <code>c$</code>, <code>*$</code> and <code>!$</code>
sentinels in fixed form, <code>gfortran</code> needs to be invoked with
the <samp>-fopenacc</samp>.  This also arranges for automatic linking of
the GNU Offloading and Multi Processing Runtime Library
<a href="https://gcc.gnu.org/onlinedocs/libgomp/index.html#Top">libgomp</a> in <cite>GNU Offloading and Multi Processing Runtime
Library</cite>.
</p>
<p>The OpenACC Fortran runtime library routines are provided both in a
form of a Fortran 90 module named <code>openacc</code> and in a form of a
Fortran <code>include</code> file named <samp>openacc_lib.h</samp>.
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